Objectives:Land subsidence caused by long-term over-exploitation of ground water is one of major problems in Beijing.Since the opening of the South-to-North Water Transfer Project,the problem of water shortage in Beijing has been greatly alleviated,and the pressure of land subsidence has been re-duced to a certain extent.Methods:In order to analyze the development of land subsidence after the start of the South-to-North Water Transfer in Beijing,ascending and descending time-series interferometric syn-thetic aperture radar(InSAR)technique is used to monitor land subsidence in Beijing.First,the mean defor-mation velocity and cumulative deformation in line of sight in Beijing from January 2015 to December 2020 is obtained by the small baseline subset InSAR.Second,the robust least square fitting method is used to fuse the deformation results of the lifting rail,after that the global positioning system monitoring data are compared with the fusion results of lifting rail.Finally,the variation trend between the deformation results obtained by the robust least quadratic fitting and groundwater data is analyzed.Results:The deformation re-sults show that the center of Beijing is basically stable and the deformation distribution is not uniform.The maximum ascending annual deformation velocity and the maximum ascending cumulative deformation amount reach-134 mm/a and-697 mm respectively.The maximum descending annual deformation ve-locity and the maximum descending cumulative deformation amount reach-135 mm/a and-734 mm re-spectively.And the fusion results obtained by the least square fitting method has reliability and accuracy.Conclusions:The subsidence rate in Beijing shows a decreasing trend with the gradual increase of ground-water level.In general,the middle route of South-to-North Water Transfer Project has alleviated the ex-pansion trend of land subsidence in Beijing to a certain extent.
关键词
地面沉降/时序InSAR/升降轨/抗差最小二乘拟合/南水北调
Key words
land subsidence/time-series InSAR/ascending and descending/robust least squares fitting method/South-North water transfer
维普
万方数据